[es6] implement destructuring assignment

src/prettyprinter.cc

Index: src/prettyprinter.cc
diff --git a/src/prettyprinter.cc b/src/prettyprinter.cc
index f50d5904d0a50ce0ed49c4de9c7121f8d03b7e0d..5aefe7c20217ec5d77db168d2679ad3794867c94 100644
--- a/src/prettyprinter.cc
+++ b/src/prettyprinter.cc
@@ -251,6 +251,11 @@ void CallPrinter::VisitRegExpLiteral(RegExpLiteral* node) {
 }
 
 
+void CallPrinter::VisitAssignmentPattern(AssignmentPattern* node) {
+  Visit(node->pattern());
+}
+
+
 void CallPrinter::VisitObjectLiteral(ObjectLiteral* node) {
   for (int i = 0; i < node->properties()->length(); i++) {
     Find(node->properties()->at(i)->value());
@@ -734,6 +739,11 @@ void PrettyPrinter::VisitRegExpLiteral(RegExpLiteral* node) {
 }
 
 
+void PrettyPrinter::VisitAssignmentPattern(AssignmentPattern* node) {
+  Visit(node->pattern());
+}
+
+
 void PrettyPrinter::VisitObjectLiteral(ObjectLiteral* node) {
   Print("{ ");
   for (int i = 0; i < node->properties()->length(); i++) {
@@ -1465,6 +1475,12 @@ void AstPrinter::VisitRegExpLiteral(RegExpLiteral* node) {
 }
 
 
+void AstPrinter::VisitAssignmentPattern(AssignmentPattern* node) {
+  IndentedScope indent(this, "ASSIGNMENT PATTERN", node->position());
+  Visit(node->pattern());
+}
+
+
 void AstPrinter::VisitObjectLiteral(ObjectLiteral* node) {
   IndentedScope indent(this, "OBJ LITERAL", node->position());
   EmbeddedVector<char, 128> buf;